NFL has considered widening the playing field 35 feet, and reportedly may revisit the idea

The NFL reportedly might consider widening the playing field to Canadian Football League standards, a drastic idea that would be one of the bigger rules changes the game has seen in a long time – if it comes to pass.
The National Football Post reported that the league has talked about widening the field sideline-to-sideline from 160 feet to 195 feet, which is the CFL standard, and the league might look into the idea again this offseason.

The National Football Post said the competition committee discussed the idea a year ago. In theory, a wider field would be safer for a league that has much bigger and faster players than it did decades ago.
“I’m not so sure we shouldn’t think about widening the field,” former competition committee member Bill Polian told the National Football Post. “It’s a radical idea, but I think it’s worth thinking about. You would have more space and perhaps a safer game. I say that based on my CFL experience. There are less collisions of that type in the Canadian game.”
The idea of a wider field is radical, and although the league needs to improve player safety, it seems like changing the dimensions of the field would take a lot of convincing to a league that doesn't make major modifications very often.
The National Football Post story made the counter-argument that the wider field might not necessarily help player safety, because players would have more room to build up speed and have bigger collisions.

There would be many logistical issues. Many stadiums were built with the 160-foot wide field in mind, with every foot of possible room used for seats that generate revenue. Widening the field by more than 10 yards might make the playing area inside the stands a bit snug. Also, for teams that use the fields for college or high school state playoff games, converting between the two would be a difficult task. Also, there's the fact that it's hard to imagine the NFL changing one of the basic foundations of the game after so many years with the same size field. The last change this drastic might be when the league moved the goal posts from the goal line to the back of the end zone in 1974.
Changing the width of the field would be a major change to the game, and while it doesn't logically seem very likely to happen soon, the NFL needs to look at every possibility to quell the negative publicity over player safety issues.